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What are Gemstones?
The Structure of Gemstones and their Imitations
The Gemstone Industries
4 other sections not shown
abrasion Africa agate alexandrite amber amethyst ancient aquamarine artiﬁcial Be/ow beads beryl blue Brazil brilliant cut brooches brown Burma cabochons cameos carats carved cat’s-eyes century Ceylon chalcedony chemical chrysoberyl chrysoprase collectors coloured stones colourless corundum crown crystal structure density deposits diamond dichroism emerald facets feldspar ﬁelds ﬁnd ﬁne ﬁnest ﬁre ﬁrst ﬂat ﬂuorescence garnet gem species gemstones girdle glass gold gravel green hardness identiﬁcation igneous rocks imitations inﬂuence jade jadeite jasper jewellery jewels lapis lazuli layers light lustre mainly Malagasy material metals metamorphic mined mineral species moonstone natural nephrite occur opal origin pearls pegmatites pendants peridot pink polished precious produced pyrope quartz rare reﬂected refractive index rock crystal rubies and sapphires sapphire shape silica soft sometimes specimens spinel surface synthetic taaffeite temperature topaz tourmaline translucent transparent turquoise usually variety wear weight worn yellow zircon